Is unified memory on NVIDIA DGX Spark 128GB as fast as VRAM for Yi 1.5 6B?

Not always. NVIDIA DGX Spark 128GB can often fit larger models thanks to unified memory, but a discrete GPU with dedicated high-bandwidth VRAM may still decode faster once the model fits. For this combination, the important distinction is capacity versus sustained throughput.

Can Yi 1.5 6B run on NVIDIA DGX Spark 128GB?

YES — With F16

C42Usable

Estimated from fit model

Yi 1.5 6B needs ~27.5 GB VRAM. NVIDIA DGX Spark 128GB has 0 MB. With F16 quantization, expect ~20 tok/s.

Runtime: OllamaCapacity: RoomyBandwidth: LowStack: BasicBottleneck: Balanced

Operating mode

Choose the run profile you care about

Interactive favors responsiveness, while light API and scale-out lean harder on serving readiness. The fit stays the same, but the recommendation lens changes.

Current mode

Balanced

Balanced for general local use. Keeps the ranking neutral across personal and serving workflows.

Yi 1.5 6B at Q4_K_M needs 5.8 GB — too much for NVIDIA DGX Spark 128GB (0.0 GB). Runs at F16 (27.5 GB) with maximum quality. 8 quantization levels fit.

Capabilities:

Select quantization to explore

Q4_K_M (Medium quality) — 18.9 GB, 48.7 tok/s, Runs well

18.9 GB required108.8 GB available

17% VRAM used

Fit status

Runs well

Decode

48.7 tok/s

TTFT

3978 ms

Safe context

Memory

18.9 GB / 108.8 GB

Memory breakdown

Weights3.7 GB

KV Cache1.0 GB

Runtime1.2 GB

Headroom13.1 GB

See how fast it feels

See how fast it feelsYi 1.5 6B on NVIDIA DGX Spark 128GB
1st promptCold start — includes initialization
>What is local AI inference?
Local AI inference means running an AI language model directly on your own hardware — your laptop, desktop, or server — instead of sending requests to a remote cloud API.

When you run inference locally the model weights are loaded into your GPU or unified memory. Each token you generate requires reading those weights from memory, so memory bandwidth is the main bottleneck for decode speed.

Key benefits of running locally:
  - Full privacy: your prompts never leave your machine
  - No per-token cost or rate limits
  - Works offline once the model is downloaded
  - Latency depends only on your hardware
2nd promptWarm — model ready, no init overhead
>How much VRAM do I need?
It depends on the model size and quantization level. A rough rule of thumb:

  Model size     Q4 (4-bit)    Q8 (8-bit)    FP16
  7B params      ~4.3 GB       ~7.5 GB       ~14 GB
  13B params     ~7.9 GB       ~13.9 GB      ~26 GB
  70B params     ~42.7 GB      ~74.9 GB      ~140 GB

Most people use 4-bit quantization (Q4_K_M) which gives 90-95% of full quality at a fraction of the memory. A 24 GB GPU can comfortably run most 7B-13B models.
Estimated: 48.7 tok/s decode · 4.0s TTFT (warm) · 122 tok/s prefill

What limits this setup

This setup is broadly balanced for this model.

Shared-memory contention still exists

The OS, browser, and inference runtime all compete for the same physical memory pool, so real-world headroom is less forgiving than raw capacity suggests.

Best improvement path

Performance by workload

Workload	Grade	Fit	Decode	TTFT	Context
Chat	C	Runs well	48.7 tok/s	2170 ms	4K
Coding	F	Too heavy	8.1 tok/s	24033 ms	4K
Agentic Coding	C	Runs well	48.7 tok/s	5786 ms	4K
Reasoning	C	Runs well	48.7 tok/s	4701 ms	4K
RAG	C	Runs well	48.7 tok/s	7232 ms	4K

Quantization options

How Yi 1.5 6B (6B params) fits at each quantization level on NVIDIA DGX Spark 128GB (92.2 GB usable).

Quant	Bits	VRAM	Quality	Fit
Q2_K	2	2.3 GB	Low	D39
Q3_K_S	3	2.9 GB	Low	D39
NVFP4	4

Get started

Copy-paste commands to run Yi 1.5 6B on your machine.

Run

lms load Yi-1.5-6B-Chat && lms server start

Upgrade options

Hardware that runs Yi 1.5 6B well

NVIDIA H200 141GBBudget pick

141 GB VRAM (+13)4800 GB/s (+4527)

Raises estimated decode speed by about 72%.84 tok/s decode

Raises estimated decode speed by about 72%.

Adds memory headroom for longer context windows and future model growth.

~$30,000 MSRP

NVIDIA H200 PCIe 141GBBest value

141 GB VRAM (+13)4800 GB/s (+4527)

Raises estimated decode speed by about 72%.84 tok/s decode

Raises estimated decode speed by about 72%.

Adds memory headroom for longer context windows and future model growth.

~$30,000 MSRP

NVIDIA B200 180GBNVIDIA upgrade

180 GB VRAM (+52)8000 GB/s (+7727)

Raises estimated decode speed by about 72%.84 tok/s decode

Raises estimated decode speed by about 72%.

Adds memory headroom for longer context windows and future model growth.

~$30,000 MSRP

Frequently asked questions

Can NVIDIA DGX Spark 128GB run Yi 1.5 6B?

Yes, NVIDIA DGX Spark 128GB can run Yi 1.5 6B at F16 quantization (Runs well). The recommended Q4_K_M requires 5.8 GB which exceeds available memory, but at F16 it needs only 27.5 GB. Expected decode speed: 20.3 tok/s.

How much VRAM does Yi 1.5 6B need?

Yi 1.5 6B (6B parameters) requires approximately 5.8 GB at Q4_K_M quantization. On NVIDIA DGX Spark 128GB, it fits at F16 using 27.5 GB.

What is the best quantization for Yi 1.5 6B?

The recommended quantization is Q4_K_M, but on NVIDIA DGX Spark 128GB the best fitting quantization is F16, which uses 27.5 GB.

What speed will Yi 1.5 6B run at on NVIDIA DGX Spark 128GB?

On NVIDIA DGX Spark 128GB, Yi 1.5 6B achieves approximately 20.3 tokens per second decode speed with a time-to-first-token of 9549ms using F16 quantization.

Can NVIDIA DGX Spark 128GB run Yi 1.5 6B for coding?

For coding workloads, Yi 1.5 6B on NVIDIA DGX Spark 128GB receives a F grade with 8.1 tok/s and 4K context.

What context window can Yi 1.5 6B use on NVIDIA DGX Spark 128GB?

On NVIDIA DGX Spark 128GB, Yi 1.5 6B can safely use up to 4K tokens of context at F16 quantization. The model's official context limit is 4K, but available memory constrains the safe maximum.

See all results for NVIDIA DGX Spark 128GB See all hardware for Yi 1.5 6B

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